net: stmmac: Use hrtimer for TX coalescing
This driver uses a normal timer for TX coalescing, which means that the
with the default tx-usecs of 1000 microseconds the cleanups actually
happen 10 ms or more later with HZ=100. This leads to very low
througput with TCP when bridged to a slow link such as a 4G modem. Fix
this by using an hrtimer instead.
On my ARM platform with HZ=100 and the default TX coalescing settings
(tx-frames 25 tx-usecs 1000), with "tc qdisc add dev eth0 root netem
delay 60ms 40ms rate 50Mbit" run on the server, netperf's TCP_STREAM
improves from ~5.5 Mbps to ~100 Mbps.
Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Link: https://lore.kernel.org/r/20201120150208.6838-1-vincent.whitchurch@axis.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index c88ee8e..e553b9a 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -13,6 +13,7 @@
#define DRV_MODULE_VERSION "Jan_2016"
#include <linux/clk.h>
+#include <linux/hrtimer.h>
#include <linux/if_vlan.h>
#include <linux/stmmac.h>
#include <linux/phylink.h>
@@ -46,7 +47,7 @@ struct stmmac_tx_info {
struct stmmac_tx_queue {
u32 tx_count_frames;
int tbs;
- struct timer_list txtimer;
+ struct hrtimer txtimer;
u32 queue_index;
struct stmmac_priv *priv_data;
struct dma_extended_desc *dma_etx ____cacheline_aligned_in_smp;